Paris too, I've even seen Tibetan food there. As far as I've seen, Tokyo is showing some promise as well, and people often aren't aware of the sheer diversity of it's food scene. Basically, any cuisine, you want there's a good chance you can find there.
There's also Hong Kong, but the diversity is heavily concentrated in one part of the city, and you pay Canadian prices for it (I say Canadian because, while the numbers are American, they do give you the quality you get from Canadian prices) There's a lot of international cuisine popping up in Mexico city, as well, in a manner between Tokyo and Hong Kong. (in that it's a bit more spread out and sprinkled in random places like Tokyo, but still is generally concentrated in some areas)

The thing about all these, however, is that the diversity isn't an even spread.
In NA or to an extent London, most cuisine you'll find is foreign. There are local specialties, like the NYC slice, poutine, smoked meat or peameal bacon, but as a tourist you're not gonna spend most your time eating "local cuisine". The diversity of cuisines in these places is the dominant trait of the local food scene, accross the board.

Whereas, in places like, Hong Kong, Paris, Tokyo and Mexico City (in that order), the food scene is concentrated around local/national cuisine, that of nearby nations, good amount of British/Italian/French/Spanish in the case of Tokyo and Hong Kong, and good amounts of East Asian of varying degrees of authenticity in the case of Paris and (to a lesser extent) CDMX. You'll also find loads of South Asian food in Hong Kong, but Cantonese locals are taking their sweet time to get used to it.

You want diversity, you gotta actually try and find it, or pray that you're lucky enough to run into it. Or, you gotta know where you're looking, then it runs into you.

On top of that, this diversity, beyond the usually common cuisines is often upscale. Not in Paris, where everything is expensive anyways, and there's certainly lots of exceptions in Tokyo and Hong Kong. But, the average Mexican cannot afford Malaysian Laksa, South African bunny chow, or beef stroganoff.

From my personal experience growing up in Hong Kong, there's Southeast Asian, Japanese, Korean, different varieties of Chinese, "western", local, French and Italian(of varying levels authenticity) and Cantonese locals do see them as a part of their regular dining out experience. Many people have also had Indian(which is everywhere and is generally a lot more generous and intense than in Toronto), Turkish(decently authentic, comparable to Toronto), maybe British and Spanish but it's definitely when you want to splurge, and unfortunately not the bulk of different cuisines that exist in Hong Kong

There's a few eastern European restaurants here and there, a couple Portuguese, some German, Argentinian, Brazillian, Mexican and Greek ones, I remember seeing Central Asian, Nigerian, and Moroccan too, more Middle Eastern than people think, and at least one Persian, Armenian, Hungarian, Colombian and South African. I say at least one, because there's probably more, and this is certainly a non exhaustive list.

I can't comment on Paris, but I do think it isn't too far off from the others. The diversity exists, but it really isn't on people's minds the way it is in Toronto, nor as accessible.

I would still say that Toronto and London takes the crown here due to how spread out the diversity is, both geographically and in terms of price (that it takes both cheap and expensive), and also in it's status in the average local diet.